PSYB20H3 Chapter Notes - Chapter 3: Stillbirth, Small For Gestational Age, Cardiovascular Disease
Document Summary
Gestation: the prenatal period of development between conception & birth. Growth and motor development occur from the top down and from center of the body outward. Cephalocaudal principle: dictates that development proceeds from the head to the. Proximodistal principle: development proceeds from parts near the center of the lower part of the trunk (cid:523)(cid:498)head to tail(cid:499)(cid:524) Embryo"s head, brain, and eyes develop earliest body to outer ones (cid:523)(cid:498)near to far(cid:499)(cid:524) Embryo"s head and trunk develop before the limbs, arms and legs before fingers. Germinal stage: includes the first two weeks of development after fertilization. The zygote divides and becomes more complex and is implanted in the wall of the uterus. Cells arrange into a hollow sphere (with the inner cell mass) Within 36 hours of fertilization: zygote enters a period of rapid cell division and duplication (mitosis) 72 hours: 16 32 cells; 24 hours later: 64 cells begins to implant on uterine wall.
